Refrigerating apparatus



' G. H. CLARK REFRIGERATING APPARATUS Dec. 10, 1940.

Filed Feb. 25, 1959 lNVENTOR ZKW/KM AU, ATTORNEY Patented Dec. 10, 1940UNITED STATES PATENT OFFICEv REFRIGERATING APPARATUS poration ofMichigan Application February 23, 1939, Serial No. 257,857

16 Claims.

My invention relates to new and useful improvements in refrigeratingapparatus and more particularly to flow controlling devices forcontrolling the flow of refrigerant in a refrigerating system.

An object of my invention is to provide a device operable to control theflow of refrigerant medium in a refrigerating system so that a motor ofsmall power output may be used'in a system which without my inventionwould require .a inotor of larger power output.

Another object of my invention is to provide a device operable toprevent overloading of the refrigerant compressor motor due towarmevaporator temperature at time of pull-down.

Another object of my invention is to provide means to preventoverloading of the motor by limiting the suction line pressures to thecondensing unit.

Another object of my invention is to provide a means for controlling theflow of refrigerant to a refrigerating unit so that the motor iseffectively unloaded each ,cycle during normal operation of the system.A

Another object of my invention-is to cool the liquid being supplied tothe evaporator to thereby prevent vaporization ,of the supplied liquidprior to reaching the evaporator.

Another object of my invention is to provide 45 a part of'thisspecification,I have fully and' clearlyillustrated a preferredembodiment of my invention, in which drawing-- g The figure is a view invertical central section of a control device embodying y invention and50 shown in cooperative relation in a refrigerating system which isdiagrammatically illustrated.

Referring to the drawing by characters of reference, designatesgenerally my control device connected to .a refrigerating systemcomprising 55 a suction line 2 leading from the device I to a a combinedheat exchanger and pressure regu o lating unit for controlling theloading of the con'-' refrigerant compressor 3 driven by an electric endof a radiator or condenser III which has its other or outlet endconnected to a strainer mem- 10 her The compressor 3, conduit 9,condenser I0, motor 4 and belt 5 comprise what is known to the art as acondensing unit, and which is generally designated in the drawing by thenu meral l2. The strainer member H is connected 15 intermediate theoutlet of the condenser l0 and one end l3 of a liquid feeding orso-called capillary tube, generally designated 14, and removes anyforeign matter which might be in the refrigerant and mightclog the tubeM. The other 20 end I5 of the capillary'tube I4 is communicativelyconnected to one end l6 of a, conduit member I! having its other endconnected to the inlet l8 of the evaporator or cooling element 8. The

outlet I9 of the evaporator 8 is connected by 25 means of a conduit 20to the control device I, U and counnunicates therethrough with thesuction line 2. The particular way in which the tube M is connected tothe liquid feeding conduit l1, and

the suction conduit 20 is connected through the 30 device I to thesuction line 2 will be more particularly pointed outhereinafter. Thecontrol device I, conduits l7 and 20, as well aspthe evaporator B, arepreferably located in the space to be refrigerated.

The control device I comprises a body or hollow conduit member 2| openat either end and having an integral, transverse wall 22 separating thebody 2| into two open ended chambers 23, 24, which chambers may betermed the valve inlet and valve outlet chambers, respectively. Thechamber 23 is preferably of larger capacity than chamber 22 which,considering its cooperating parts, is kept as small as manufacture makeseconomically feasible. The chamber 23 is closed 5 at its open end bymeans of a plate member 25 suitably-secured in and sealed to the endportion 26 of, the conduit member 2|. The plate member 25has a pair ofapertures therethrough in which are secured and sealed, by suitablemeans such as solder 21, tubular conduit members 28, 29. q

The end portions of the members 28, 29 which are external of the chamber23 receive the conduits 20, I1, respectively, which conduits are securedin fluid-tight relation therein. The member 28 is open at its other enddirectly to the chamber 23 to establish communication between the outletside |9 of the evaporator 8 and the chamber 23. The end of the member 23located within chamber 23 receives the end l5 of the capillary tube M toestablish a fluid-tight communication system extending from thecondensing unit l2 through tube l4 and the conduit" to the inlet |8 ofthe evaporator 8.

Preferably the portion of the tube |4 between the condenser end I3 andthe chamber 23 is maintained as short as possible and the tube |4preferably extends from the condensing unit I 2 through a suitablefitting 30 and through the interior of the suction line 2 to the valvebody 2|. The internal boreof the suction tube or line 2 should besubstintially larger than the external diameter of the tube l4 so thatthe refrigerant vapors will pass through the tube to the compressor 3with but slight -frictional losses. The

tube |4 passes through an aperture 3| in the transverse wall 22 andthence the tube |4 passes into the chamber 23 where the remainder of thetube is coiled into a helix, or other suitable form 32. It is desired tolocate'within chamber 23 as much of the tube l4 as is practical, for apurpose to be hereinafter described. The tube i4 is sealed within theaperture 3| in fluid-tight. relation to the wall 22 so that the fluidwithin chamber 23 will notpass through aperture 3| and thence to thesuction line 2 or chamber 24.

The open end of chamber 24 is closed by means of a diaphragm 33 sealedin fluid-tight relationship to the body 2| to thereby render the chamber24 a pressure responsive chamber. Overlying the diaphragm 33 and securedto the body 2| in fluid-tight relationship is a cap member 34 having acentrally disposed internally threaded aperture 34 within an extendedportion 34 ofthe cap member 34. Screwthreaded into the aperture 34 is anadjustment cap member 35 having a cross bar 36 which is rigidly securedto the member 35 and serves as a convenient handle for screwing themember 35 relative to the cap member 34 for purposes to be hereinafterdescribed. A readily flexible and resilient cap member 31, which may bemade of rubber or similar material, is placed on and in such a mannerthat it will cooperate with the portion 34 and the interior of member 34to form a sealed chamber over the diaphragm 33. The resilient member 31in its inert state is preferably of such a dimension that it must beflexed or stretched when in its cooperative position on the portion 34of the cap member 34 to insure a substantially fluid-tight seal betweenthe members 34 and 31. Upon flexing of the diaphragm 33 a portion of thefluid within cap member 34, due to the volume change within the member34, is forced through an aperture 31 in the member 35, which apertureleads from the interior of the cap member 34 to the interior ofresilient member 31." The resilient member 31 will adjust itself to thechange in fluid content by a slight change in volume, and it may thusbe-seen that as the'diaphragm 33 flexes, the fluid enclosed by members34, 31 remains confined and the resilient member 3 Lacts as a breatherchamber for the chamber defined by member 34 and diaphragm 33. Thepurpose of this construction is to prevent undue moisture depositingwithin the cap member 34 or on the diaphragm 33, due to the-coolconditions of the diaphragm 33 or member 34, which may exist under sometypes of operation and which would occur if the member adjacent theportion 40 surrounding atmospheric air, which inevitably containsvarious quantities of water vapor, were continually being admitted andemitted.

Concentric with the threaded aperture 34a and extending through thetransverse wall 22 is an aperture 38, preferably circular incross-section, which serves as a passageway connecting the chambers 23,24. Integral with the transverse wall 22 and extending therefrom intochamber 23 around the aperture 38 is an annular seating surface or valveseat 38. A valve member 40 has a disk portion 4|] which cooperates withthe seat 39 to control flow of fluid through aperture 38. One endportion 4| of the valve member 40 extends upwardly from the portion 40through the aperture 38 into chamber 24 and has its end surface abuttingagainst an abutment member 42, which member 42 is carried adjacent theunderside of the diaphragm 33 in a suitable manner, such as by a spidermember 42*, and the member 42 is free to move therewith. A section 43.of the end portion 4| which is within the aperture 38 may be rectangularin cross-section and have a diagonal dimension slightly less than thediameter of the aperture 38 to provide segmental passageways for thepassage of fluid from chamber 23 to chamber 24. The corners of thesection 43 guide the valve member 40 in its reciprocation in theaperture 38. Extending downward from the portion 40 is a portion 44 ofreduced diameter which abuts against a raised portion or abutment 45 on,the plate member 25 to limit movement of the valve member 40 in a valveopening direction and also to limit inward flexing of the diaphragm 33.The raised portion 45 also serves to locate one end of a helical coilspring 46 having its other end positioned by a shoulder portion 46 onthe The spring 46 acts to urge the valve member 40 toward closedposition.

Located above the diaphragm 33 is a second helical coil spring 41 havingone end thereof -abutting against an abutment member 48. The member,48is supported by means of a spider member 48 having engagement with theupper side of the diaphragm 33, and in such a manner that the abutmentmember 48 is free to move with the diaphragm 33. The upper or oppositeend of the spring 41 abuts against an abutment or spring seat member 49.Within the hollow cap. member 35 and projecting downward from the upperend wall thereof, there is a bearing member having a conical or pointedend portion which is received in a socket or recess, preferably conical,in the top face of seat member 49 so that it makes a point contact atthe center of rotation of the member 35. The member 49 is therebypermitted to. adjust itself to the plane of the abutting surface of thespring 41, and the spring is allowed to adjust itself to a more evenengagement with and to evenly distribute its resilient force. over theentire surface of the abutment member 48. This point contact alsoreduces to a minimum the friction opposing screwing movement of themember 35 within the threaded aperture 34 due to the reduction of thefrictional force between the members 49 and 35.

The operation'of my device will be more clearly pointed out as follows:The control device I may, for purposes 'of exposition, be studied firstfrom the liquid feeding viewpoint and secondly from the viewpoint of asuction line pressure control valve member. The liquid feeding orcapillary tube element I4 is preferably a small bore conduit member andshould be so proportioned that when the condenser I is condensing thegaseous refrigerant vapor compressed by the compressor 3 at condensertemperatures, the restriction to flow or pressure drop of the liquid 50condensed in the condenser l0 and flowing through the tube 14 from thestrainer member H to the inlet I6 of the member ll at the ratesubstantially equal to the rate at which the liquid is condensed, issubstantially equal to the difference in pressure between that necessaryto condense the vapor at in the condenser so that at the refrigeranttemperature in the condenser the refrigerant vapor will condense toliquid form. The tube I 6 is also proportioned so that normally onlycondensed liquid flows through the tube Hi to the evaporator 8 and atarate substantially equal to therate at which the refrigerant iscondensed in the condenser ID. The liquid condensed in the condenser I0therefore does not tend to fill up the condenser and thereby reduce thecondensing or heat radiating capacity of the condenser 10 with constanttemperature condensing medium, air in the, present instance, andconstant condensing temperature of the refrigerant. I have found frompast experience that with a condensing unit such as is normally'used inthe art for household or domestic refrigeration purposes, a tube of .031inch diameter bore and of 8.5 feet in length operates satisfactorilywith dichlorodifiuoromethane (Freon 12) at the normal operatingtemperatures and pressures found in a domestic refrigeration system. -Ihave also found that a tube having an internal diameter bore of .040inches and being 12 feet long will work satisfactorily in.

' a methyl chloride system designed for household or domesticrefrigeration and employing a condensing unit having approximately 1000cubic in./min. displacement. It is to be understood that other diameterbores and lengths of tubing may be employed with similar results for thesame conditions of operation. When different operments.

ating temperature or pressure conditions are desired, or different sizesof condensing units are employed, it is well known and evident to thoseskilled in the art that the length and bore of the tube will be requiredto be altered in accordance with any change in the refrigerating systemele- The operation of the tube l6 under normal temperature or operatingconditions, to be hereinafter described, is similar to but distinguishesfrom that of the prior art capillary tube as will be evident from thespecification.

The control valve will now be described as a suction line pressurecontrol and it will be assumed, for purposes of exposition, that thesystem is located within a 70 F. room and the condensing unit has notbeen operating for a considerable period of time so that the entirerefrigerating system has assumed ambient or room temperature. It is aninherent characteristic of a capillary tube refrigerating system thatthe liquid refrigerant during the off periods of the condensing unitwill be in the evaporator or low side cooling coil and such operation iswell known to those skilled in the art. In the system embodying mycontrol device, the adjustable cap member 35 is so positioned relativeto the member 34 that the tension or force exerted by the spring 41,plus the force exerted by the pressure of the fluid or atmosphericpressure acting on the upperside or spring 41 side of the diaphragm willbe so balanced against the force of spring 46 and the pressure acting onthe diaphragm within chamber 24 that the valve member 40 Will be inclosed position when the pressure within chamber 24 is slightly inexcess of a pressure equal to the upper limit of the pressure which ismaintained within the evaporator 8 during the .timr the evaporator isfunctioning to maintain the desired normal cooling temperatures. In thecase of a household refrigerating system, I have found that an averageevaporator temperature of 15 F. is satisfactory in most instances, but Ihave found that there are times when the desired evaporator temperaturemay be as high or higher than F. Regardless of the exact temperatureunder which the evaporator is operated, the valve will function in muchthe same manner, the only difference being that with change in desiredevaporator temperature, the adjustmentoi the member must be changed sothat the pressure in chamber 24 at which the valve will close is raisedor lowered to thereby determine the predetermined maximum pressure abovewhich the valve 40 will begin to throttle the evaporator outlet to thesuction line to limit'the pressure on the suction side of compressor 3to prevent the motor 6 from overloading. It is also to be understoodthat the evaporator may be operatedover a range of evaporatortemperatures below the temperature corresponding to the predeterminedmaximum temperature, without change in the valve setting, by merelychanging the temperature at which "the bulb I will operate'the switch 6controlling the motor 4. It is not impossible for the refrigerantpressure in the evaporator to be above the predetermined pressurein caseof temperature rise above the desired evaporator temperature, but suchrise will cause the valve 40 to throttle the refrigerant flow to thecompressor 3 and the system will not be operating at maximum compressorsuction pressure.

The cpndensing unit for preferred operation is so proportioned relativeto the operating temperature of the evaporator and the control valvethat when the highest evaporator temperature is being maintained, or thepressure of the refrigerant therein is as high as will occurduringnormal operation, the motor 0 will be operating at its continuousmaximum power output. In actual. practice a small margin of safety ismaintained to prevent damage to the condensing unit should more power berequired for any reason.

The cap member 35 is so adjusted that upon pressure in excess ofthenormal operating pressure in the chamber 24 the valve 40 will move toclosed position and further increase in pressure therein, due torefrigerant pressure in the evaporator 8, is prevented. When thecondensing unit is started under the condition assumed hereinbefore, andcommonly known to the art as pull-down, the pressure within the suctionline is substantially that of normal operation, while the evaporatorpressures are greatly in excess of the normal operating pressure and theevaporator pressure is directly determined by ambient temperature. Uponstart of the condensing unit the pressures in the suction line 2andchamber 2d are lowered slightly, and with the slight low ering ofpressure the force acting on the diaphragm 33 will be unbalanced and thevalve member 60 will move toward open position to admit vapor from thechamber 23' at a rate sufficient to maintain the maximum pressure forwhich the valve is set to close. In this manner I am able to start mycondensing unit and operate the compressor at suction and dischargepressures during pull-down which are but slightly above normal but notenough to-injuriously affect the motor, and I am therefore not requiredto install a larger capacity motor to "pull-down" the system to preventthereby a serious motor overload, so that after the unit has beenbrought to operating temperatures and pressures I use only a portion ofthe power output which the motor is capable of producing. The advantagesof using the motor 4 at maximum output at normal refrigerating pressureswill be evident to those skilled in the art. As the temperature andpressure of the evaporator is lowered duringfpull-down, the valve 40will gradually open wider in an effort to maintain the predeterminedpressure within the chamber 24. As the pressure within the evaporator 8low-e ers to normal operating pressure, the valve 48 moves to wide openposition and remains in that position so long as the pressure in theevaporator 8 remains below the predetermined pressure for which thevalve 40 is set to close.

As pointed out hereinbefore, the evaporator outlet conduit 20 dischargesinto the chamber 23 in which the helical coil 32 of the tubing I4 isalso located. This chamber 23 serves as a combination liquid trap andheat exchanger to prevent the passage of liquid refrigerant from theevaporator to the suction line 2. Any liquid coming through theconduit.20 is evaporated in the chamber 23 either by the heat of theambient medium conducted thereto through the walls of the casing 2| orfrom the heat of the condensed, relatively warm refrigerant in thehelical coil 32 of the tubing It. It was pointed out hereinbefore thatit was preferable to maintain'the suction line 2 and the portion of thetube I4 located therein, or the portion between the end 13 and theaperture 3|, as short as 'is conveniently possible. In this manner Ilocate as much of the tube H as is possible in the chamber 23, andtherefore as much of the warm liquid refrigerant flowing to theevaporator 8 in heat exchange relation with the cold suction vapor fromthe evaporator as is "possible. Additional heat exchange will beaccomplished along the portion of the tube 14 which is located withinthe suction line 2. This portion within suction line 2 is at the highertemperature, the liquid refrigerant dropping in temperature and pressureas it flowsthrough the capillary tube i4, and this portion withinsuction line 2 is also iii-contact with the warmest suction line vapors.The heat exchange system is, broadly speaking, therefore of the wellknown counter-flow type. In event of any leak by the valve 40 fromchamber 23 to chamber 24, which might occur during periods when thepressure within the evaporator 8 and chamber 23 are above thepredetermined pressure at which valve 48 is set to close, a highpressure may be developed in the suction line 2 and chamber 24. If thechamber 24 is as small as possible and the suction line 2 is as short aspossible, the actual volume of high pressure vapor is relatively'smalland the temporary overload on the motor 4 is easily handled thereby. Itmay also be pointed out that in such a condi tion the differentialacross the compressor 3 is low and a low motor starting torque only isnecessary, in fact, less torque than would be required had the valve 40not allowed vapor to leak from chamber 23 to chamber 24.

In the prior art capillary tube systems in which a pressure limitingdevice such as has been invented by me and disclosed herein has not beenincorporated, at pull-down" from a high back or suction pressure on thecompressor, the compressor handled arelatively great quantity ofrefrigerant as measured in pounds per minute.

At the start of a pull-down, the actual mass of fluid handled at highsuction pressures by the compressor at constant speed is also greaterthan at low suction pressures. The liquid therefore can not flow throughthe capillary tube as fast as it accumulates in the condenser, and itbegins to back up into the condenser to eliminate a portion of thecondenser from acting to condense the vapor discharged from thecompressor 3. Pressure within the condenser in such a. case, and inprior art systems, would continue to rise at an accelerated rate untilsuch time as the increased pressure establishes a sufficientdifferential with respect to evaporator pressure to force the condensedrefrigerant liquidl through the capillary tube as fast as the liquid iscondensed. With my device, however, I limit the maximum amount ofrefrigerant handled by my compressor in a given period of time byholding the pressure of the vapor admitted to the compressor 3 below apredetermined maximum pressure. Although the pressure within thecondenser ill will rise on "pull-down with my apparatus, the increase isless than that of the prior systems and the pressure differential acrossthe compressor 3 is maintained by my apparatus substantially constant.The power required to drive the compressor 3 is proportional to-thepressure across the compressor, and also to the absolute pressure of therefrigerant admitted to the compressor for discharge at a higherpressure. With my apparatus I prevent a substantial increase in pressuredifferential across the compressor and reduce the rate of refrigerantcirculated therethrough to thereby eliminate a major factor whichrequires that a large motor be u din a refrigerating system to take careof he high power required under pull-down conditions. 7

It may be seen therefore that I have invented an improved capillary tuberefrigerating system which will operate with a smaller condensing unitdriving motor and which in many ways accomplishes the results obtainedwith the more expensive thermostatic expansion valve systems. A slightleak by my pressure controlling valve is of substantially no detrimentto my system and in fact, as pointed out hereinbefore, may actually bebeneficial to operation.

What I claim and desire to secure by Letters Patent of the United Statesis:

1. In a refrigerating system, a condensing unit having an inlet and anoutlet, a cooling means having an inlet and an outlet, conduit meansconnecting said unit inlet to said cooling means outlet, conduit meanscomprising a capillary tube feed device connecting said'cooling meansinlet to said unit outlet, and pressure sensitive means interposed insaid first-named conduit means and operable to limit the pressure atsaid unit inlet.

.2. In a refrigerating system, a condensing unit having an inlet and anoutlet, a cooling means having an inlet and an outlet, conduit meansconnecting said unit inlet to said cooling means outlet, conduit meanscomprising a capillary tube feed device connecting said cooling meansinlet' to. said unit outlet, said first-named and said second-namedconduit means being in heat exchange relation, and pressure sensitivemeans interposed in said firstnamed conduit means and operable tolimitthe pressure at said unit inlet.

3. In a refrigerating system, a condensing unit having an inlet and anoutlet, a cooling means having n inlet and an outlet, conduit meansconnecting said unit inlet to said cooling means outlet, conduit meanscomprising a capillary tube feed device connecting said cooling meansinlet to said unit outlet, pressure sensitive means interposed in saidfirst-named conduit means and operable to limit the pressure at saidunit inlet, and means for adjusting said inlet pressure.

4. In an apparatus of the character described for controlling flow offluid, a casing having an inlet chamber and an outlet chamber separatedby a wall, said wall having an aperture therethrough defining a valveport, pressure means responsive to the fluid pressure in said outletchamber, valve means cooperating with said port to control flow of fluidthrough said aperture, said pressure means being operable to actuatesaid valve means to close said port to flow of fluid upon apredetermined pressure in said outlet chamber, and conduit meanswithinsaid inlet chamber and in heat exchange relation with the fluid in saidinlet chamber.

5. In an apparatus of the character described, a casing having an inletchamber and an outlet chamber separated by an internal casing wall;

said wall having an aperture therethrough deflning a valve port, adiaphragm forming a wall of and responsive to fluid pressures in saidoutlet chamber, valve means cooperating with said port to control flowof fluid through said aperture, longitudinally movable meansinterconnecting said diaphragm and said valve means, said diaphragmbeing operable through said longitudinally movable means to actuate saidvalve means to close said port to flow of fluid upon a predeterminedpressure in said outlet chamber,

and resilient means overlying and abutting said diaphragm and operableto control said predetermined pressure.

6. In an apparatus of the character described for controlling flow offluid, a casing having an inlet chamber and an outlet chamber separatedby an internal casing wall, said wall having an aperture therethroughdefining a valve port, pressure responsive means forming part of saidoutlet chamber, valve means cooperating with said port to control flowof fluid through said aperture, said pressure means beingoperable toactu- "ate said valve means to close said port to flow of fluid upon apredetermined pressure in said outlet chamber, and a pressure reducingliquid feeding device within said inlet chamber and in heat exchangerelationship with the fluid in said inlet chamber.

7. In an apparatus of the character described, a hollow cylindricalmember having open, ends and having an internal transverse wall, saidwall having an aperture therethrough, a seat portion on said wallsurrounding said aperture, a valve member cooperable with said seatportion to control flow of fluid through said aperture, a plate memberhermetically secured to one open' end portion of and cooperable withsaid cylindrical member to define an inlet chamber, a diaphragm memberclosing and sealing the other open end portion of and cooperable withsaid cylindrical member to define an expansible-contractible pressureoutlet chamber, an outlet passageway silient means urging said valvemember into valve closed position, said valve member having a portionthereof operatively connected to said diaphragm member for operationthereby so that upon a predetermined maximum pressure in said outletchamber said valve member will be held in closed position.

8. In an apparatus of the character described, a hollow cylindricalmember having open ends and having an internal transverse wall, saidwall having an aperture therethrough, a seat portion on said wallsurrounding said aperture, a valve member cooperable with said seatportion to control flow of fluid through said aperture, a plate memberhermetically secured to one open end portion and cooperable with saidcylindrical member to define an inlet chamber, a diaphragm memberclosing and sealing the other open end portion of and cooperable withsaid cylindrical member to define an expansible-contractible pressureoutlet chamber, an outlet passageway leading from said outlet chamber,an inlet passageway leading to said inlet chamber, resilient meansurging said valve member into valve closed position, said valve memberhaving a portion thereof operatively connected to said diaphragm memberfor operation thereby so that upon a predetermined maximum pressure insaid outlet chamber said valve member will be held in closed position,and means overlying said diaphragm and operable to preventexcessmovement thereof upon a high pressure in said outlet chamber.

9. In an apparatus of the character described, a hollow cylindricalmember having open ends and having an internal transverse wall, saidwall having an aperture therethrough, a seat portion on said wallsurrounding said aperture, a valve member cooperable with said seatportion to control flow of fluid through said aperture, a plate memberhermetically secured to one open end portion of and cooperable with saidcylindrical member to define an inlet chamber, a diaphragm memberclosing and sealing-the other open end portion of and cooperable withsaid cylindrical member to define an expansible-contractible pressureoutlet chamber, an outlet passageway leading'from said outlet chamber,an inlet passageway leading to said inlet chamber, resilient meansurging said valve member into valve closed position, said valve memberhaving a portion thereof operatively connected to said diaphragm memberfor operation thereby so that upon a predetermined maximum pressure insaid outlet chamber said valve member will be held in closed position,means overlying said diaphragm member and operable to prevent excessmovement thereof upon a high pressure in said outlet chamber, and meansfor varying said predetermined pressure.

10. In an apparatus of the character described, a hollow cylindricalmember having open ends and having an internal transverse wall, a platemember hermetically secured toone open end portion of and cooperablewith said cylindrical member to define an inlet chamber, a diaphragmmember closing and sealing the other open end portion of and cooperablewith said cylindrical member to define an expansible-contractiblepressure outlet chamber, said wall. having an aperture therethrough, aseat portion on said wall surrounding said aperture,-a valve memberextending through said aperture and having an outwardly extending flangecooperable with sa d seat portion to control flow of fluid through saidaperture, said plate member having a raised portion within said inletchamber aligned with said aperture, said valve member having a portionwithin said inlet chamber cooperable with said raised portion to limitmovement of said valve member in one direction, said valve member havinga portion in said outlet chamber operativeiy engaged by said diaphragmmember for movement insaid one direction, resilient means in said inletchamber urging said valve member into valve closed positon, an outletpassageway leading from said outlet chamber, and inlet passagewayleading to said inlet chamber, said valve member being operable to stopfluid flow through said aperture upon a predetermined maximum pressurein said outlet chamber, and means over.- lying said diaphragm member andoperable to prevent excess movement thereof upon a high pressure in saidoutlet chamber.

11. In an apparatus of the character described for controlling flow offluid, a casing having an inlet chamber and an outlet chamber separatedby an internal casing wall, said wall having an aperture therethroughdefining a valve port, pressure responsive means forming part of saidoutlet chamber, valve means cooperating with said port to control flowof fluid through said aperture, said pressure means being operable toactuate said valve means to close said port to flow of fluid upon apredetermined pressure in said outlet chamber, and means within saidinlet chamber and in heat exchange relationship with the fluid in saidinlet chamber.

12. In an apparatus of the character described for controlling flow offluid, a casing having an inlet chamber and an outlet chamber separatedby an internal casing wall, means communicatively connecting saidchambers and including a valve port, pressure responsive means sensitiveto the pressure within'said outlet chamber, valve means cooperating withsaid'port to control flow of fluid through said coonnecting means, saidpressure means being operable to actuate said -valve means to close saidport to flow of fluid upon a. predetermined pressure in said outletchamber, and a pressure reducing liquid feeding device within said inletchamber and in heat exchange relationship with the fluid in said inletchamber.

13. In a refrigerating system, a condensing unit having an inlet and anoutlet, a cooling means having an inlet and anoutlet, conduit meansconnecting said unit inlet to said cooling means outlet, conduit meanscomprising a capillary' tube feed device connecting said cooling meansinlet to said unit outlet, a pressure sensitive means interposed in saidfirst-named conduit means and operable to limit the pressure at saidunit inlet. and heat exchange means positioned in said first-namedconduit intermediate said cooling means and said pressure means.

14. In a" refrigerating system, a condensing unit having an inlet and an.outlet, a cooling means having an inlet and an outlet, conduit meansconnecting said unit inlet to said cooling means outlet, conduit meanscomprising a capillary tube feed device connecting said cooling meansinlet to said unit outlet, a pressure sensitive means interposed in saidfirst-named conduit means and operable to limit the pressure at saidunit inlet, and a chambered means interposed between said cooling meansand said pressure means, said capilliary device having a portion withinsaid chambered means and in heat exchange relation with the refrigeranttherein.

15. In a refrigerating system, a condensing unit having an inlet and anoutlet, a cooling means having an inlet and an outlet, conduit meansconnecting said unit inlet to said cooling means outlet, conduitmeanscomprising a capilliary tube feed device connecting said coolingmeans inlet to said unit outlet, and pressure means interposed in saidfirst-named conduit means, said pressure means being sensitive to theinlet pressure of said unit thereby to maintain a predeterminedsubstantially constant limit of pressure at said unit inlet.

16. In an apparatus of the character described,

a hollow tubular member having open ends and having an internaltransverse wall, said wall having an aperture therethrough, a valvemember cooperable with and operable to control flow of fluid throughsaid aperture, a plate member hermetically secured to one open endportion of and cooperable with said cylindrical member to define aninlet chamber, a diaphragm member closing and sealing the other open endportion of and cooperable with said cylindrical member to define, anexpansible-contractible pressure outlet chamber, an outlet passagewayleading from said outlet chamber, an inlet passageway leading to saidinlet chamber, and means cooperable with said valve member and operableupon a predetermined maximum pressure in said outlet chamber to movesaid valve member to closed position.

GEORGE H. CLARK.

